1. Field of the Invention
The present invention relates to knee braces. More particularly, the invention relates to an improved connection device for connecting straps to a knee brace frame.
2. Description of the Related Art
The human knee generally comprises an articulating joint between the thigh and calf muscle groups that supports the weight of the body while a person is standing, walking or running. The joint is primarily held together by four small but strong ligaments, namely, the anterior and posterior cruciate ligaments and the medial and lateral collateral ligaments. The knee is a relatively weak joint and therefore knee injuries arising out of cartilage damage, ligament strain, and other causes are relatively commonplace. Knee injuries are particularly likely to occur during physical activities in which the knees are subjected to significant lateral loads. Among the numerous physical activities in which knee injuries occur, skiing and motorcycle racing have proven to be particularly hazardous.
To help prevent knee injuries, various types of xe2x80x9cpreventivexe2x80x9d knee braces have been proposed to help support and reinforce the knee. FIG. 1 illustrates one particular type of knee brace 10 that is known in the art. The illustrated knee brace 10 is adapted for use on the right leg and includes a rigid frame 11 having an upper member 12 and a lower member 14. Polycentric hinges 16 connect the upper and lower members together along the knee joint. The rigid frame 11 maintains the thigh and calf in the proper alignment and thereby prevents lateral knee joint displacement and hyperextension of the lower leg. A plurality of straps 18 is used to secure the upper member 12 and lower member 14 of the frame 11 to the respective thigh and calf portions of the leg. During fitting, each strap 18 is passed through a loop-shaped connector called a strap tab 20 and is then folded over onto itself for securement with Vecro(copyright). The strap tabs 20 are coupled to the frame 11 by rigid connection devices, called strap tab caps 22, which are attached to the outer surface of the knee brace frame 11.
FIGS. 2 and 3 illustrate a strap tab cap 22 that is known in the art for use with the knee brace of FIG. 1. The cap 22 comprises a substantially disc-shaped main body 23 formed with first and second channels 24, 26 that extend transversely across the bottom side of the cap 22. A portion of a strap tab (shown as 20 in FIG. 1) is captured within one of the channels 24, 26 such that the strap tab 20 is securely coupled to the knee brace frame 11. As best shown in FIG. 3, a pair of screw holes 28, 30 are provided on the bottom side of the cap 22. To secure the cap 22 to the frame 11, a pair of screws 32, 34 are inserted through a pair of holes 36, 38 in the frame 11 and into the screw holes 28, 30.
Although the strap tab cap 22 described in FIGS. 1-3 has proven to be an effective connection device, it has various shortcomings. For example, the strap tab cap 22 must be constructed as a relatively thick member in order to provide sufficiently deep holes 28, 30 for receiving the first and second screws 32, 34. As a result, the strap tab cap 22 has a relatively high profile and therefore projects outwardly from the side of the frame 11. The high profile of the strap tab cap 22 is undesirable because it increases the possibility that the strap tab cap 22 will catch or snag on a foreign object during physical activity.
Another significant shortcoming is related to the manner in which the strap tab cap 22 is mounted to the knee brace frame 11. Because the existing strap tab cap 22 is attached in two locations (i.e., by two screws 32, 34), the strap tab cap is rigidly fixed to the knee brace frame 11. Therefore, the strap tab cap 22 cannot rotate relative to the knee brace frame to allow for adjustment of the strap position. This is a significant problem since the straps on the knee brace must conform to the shape of the user""s leg in order to provide maximum comfort and effectiveness.
In an attempt to solve this problem, one manufacturer has proposed a rotatable strap tab mechanism wherein the cap (i.e., connection device) and the strap tab are integrated together as a single plastic member. A fastener extends through a hole in the connection device and the plastic member is able to rotate about the fastener. However, the proposed device is constructed with a high profile and is therefore undesirable for the reasons discussed above. Furthermore, the plastic structure lacks the strength necessary for effective use on a knee brace. Therefore, the proposed device has not gained widespread popularity.
Referring still to FIGS. 1-3, another shortcoming with the illustrated prior art strap tab cap 22 is the potential for the threads in the holes 28, 30 to become worn or stripped over time. When this occurs, the screws 32, 34 are no longer securely engaged within the holes 28, 30 and the strap tab cap 22 may completely detach from the frame 11 and release the strap tab 20.
Yet another shortcoming is the discomfort caused by the screws 32, 34 that are used to attach the strap tab cap 22 to the knee brace frame 11. Because the screws are inserted from the inside of the frame, the screw heads can press against the user""s leg. As a result, a relatively thick padded insert is required along the inside of the frame 11 to help minimize the discomfort. However, the padded insert does not entirely alleviate the problem and adds undesirable expense.
Yet another shortcoming is the large number of screws required for attaching the strap tab caps to the knee brace frame. A knee brace having four caps requires eight screws that can be cumbersome and time consuming to insert during assembly. Furthermore, each of the screws can back out of the holes 28, 30 in the cap 22 over time, thereby requiring maintenance by the user.
Thus, there remains a very real and substantial need for an improved strap tab cap for attaching strap tabs to knee brace frame. It is desirable that such a strap tab cap has a low profile to avoid catching or snagging on other objects during physical activity. It is also desirable that such a strap tab cap is rotatably mounted on the knee brace frame to allow for improved fitting of the straps. It is also desirable that such a strap tab cap is constructed of a durable material that is resistant to corrosion. Finally, to be practical, it is desirable that such a strap tab cap is inexpensive to manufacture and is aesthetically appealing. The present invention addresses this need.
The preferred embodiments of the present invention provide a new and improved strap tab cap adapted for securely connecting strap tabs to the rigid frame of a knee brace. The preferred embodiments of the cap are constructed with a low profile that substantially reduces the possibility that the cap will catch or snag on a foreign object. The preferred embodiments of the cap are also rotatably mounted to the knee brace frame such that the straps can be adjusted to better conform to the shape of the user""s leg.
In accordance with one aspect of the present invention, a cap is presented generally comprising: a main body formed with a central hole, at least one post projecting downward from the bottom side of the main body, and at least one channel formed along the bottom side of the main body. The cap has a rounded top surface wherein the main body has a relatively thick middle portion which tapers toward thin edges. The channel extends transversely across the cap for receiving a strap tab. The post is inserted into a slot in the knee brace frame to limit the rotation of the strap tab cap.
The preferred embodiments of the present invention have tremendous structural integrity and therefore can withstand the application of large forces over long periods of time. The preferred embodiments of the cap are also easy to assemble, inexpensive to manufacture and do not use screws that can cause discomfort to the user along the inner surface of the knee brace frame.
The strap tab cap is described herein with particular reference to use with a knee brace; however, it will be understood that the strap tab cap is equally suitable for numerous other applications.